SMTP Gawsh Darnit
 

Hey folks, it's been awhile since I've been here but I remember there were a lot of extremely intelligent participants last time, and I see a lot of their names still hanging around, so I thought maybe I would shoot a question your way.

It's not related to PHP directly, but I'm not a member of very many forums anymore, given that most of my time is taken up with work. Hopefully somebody might be able to shed some light anyways.

I'm running a dedicated server on Ubuntu which is at the moment multi tasking between running web services, database, and mail. My POP3 is working wonderfully, but I can't for the life of me figure out what's going wrong with my SMTP. I've scoured the documentation and many many tutorials, but I can't seem to connect.

I have Postfix set up with libsasl for authentication. Everything is configured, and when I telnet to localhost 25 from my shell I get what appears to be an acceptable response;


Connected to localhost.
Escape character is '^]'.
220 mail.k....s.com ESMTP Postfix (Ubuntu)
ehlo localhost
250-mail.k....s.com
250-PIPELINING
250-SIZE 10240000
250-VRFY
250-ETRN
250-STARTTLS
250-AUTH PLAIN LOGIN
250-AUTH=PLAIN LOGIN
250-ENHANCEDSTATUSCODES
250-8BITMIME
250 DSN


I have DNS A records for the mail subdomain, and MX records set accordingly. However, while I can telnet from localhost, I can't reach telnet on port 25 from my local machine. This led me to check my firewall, but my iptables is set to allow connections on port 25;


-[~] iptables -L | grep smtp
ACCEPT tcp -- anywhere anywhere tcp dpt:smtp


So the denial must be happening somewhere in postfix' main.cf, or somewhere else I can't track down. Anybody here got any ideas?

This may be stupid but have you checked any firewalls or AV software?

Not stupid at all, but no my local firewall isn't blocking the connection, and neither is my server firewall (as posted above, iptables). I have a feeling the problem lies in the postfix configuration itself, but I even tried opening mynetworks to the world, the easiest way to get blacklisted, and even that didn't work... I'm banging my head against a wall here, and while I'd love to start from a clean setup, I have too many other services running on the server to wipe it and go again.